I want to setup a new theme whilst my website is live, how can I do this?
You may want to switch to a different theme but don't want to affect your current 'live' website, while you make the transition to a new theme, this is when you should set up a 'reserve' theme.
How do I set up a reserve theme?
In the drop down menu at the top of the screen click on 'Website' > 'Edit your Website'
Next, See 'Your Reserve Theme', located at the bottom on the right, and click the underlined link 'change', to change the reserve template theme.
Click 'edit reserve website' button to make changes to your reserve website.
When you have made your updates and are ready to switch to your new theme, click the 'Swap Primary & Reserve' orange button: